1. Field of the Invention
The present invention relates to a measuring machine with a cleaning device, and more particularly to a measuring machine having a probe such as a three dimensional coordinate measuring machine, which is provided with a cleaning device for cleaning a workpiece to be measured by the probe and its vicinity.
2. Prior Art
A three dimensional coordinate measuring machine in general is comprised of a stand, a table horizontally mounted on the stand, and a column erected on the stand and movable in a horizontal direction. The column is provided with a saddle movable in a direction which is orthogonal in a horizontal plane to the moving direction of the column. A detector is provided on the saddle for vertical sliding movement.
The detector is comprised of a spindle mounted on the body of the detector for vertical sliding movement together with the body, and a probe mounted on the spindle.
The three dimensional coordinate measuring machine constructed as above operates such that the probe is moved relative to a workpiece placed on the table, in three directions, i.e. X-axis, Y-axis and Z-axis directions according to necessity, to detect coordinates of the workpiece to thereby perform measurement of the workpiece.
If a measuring surface of the workpiece has dust, chips or the like attached thereon, accurate measurement cannot be performed, resulting in a measurement error. To avoid this, it is necessary to clean the workpiece just before starting measurement.
To meet this requirement, conventionally a workpiece cleaning device has been provided, which is used such that the entire workpiece is dipped in a liquid cleaning agent of the cleaning device or high-pressure air is ejected upon the workpiece so as to remove dust, chips or the like attached on the workpiece, before the start of measurement. In some cases, measurement is carried out without previous cleaning of the workpiece.
According to the conventional workpiece cleaning device, however, in measuring a workpiece, the workpiece once cleaned is removed from the cleaning device, and then placed onto a predetermined portion of the measuring machine. Therefore, fine dust or the like can be attached to the workpiece in the course of removal and placement of the workpiece, thus providing a possibility of a measurement error. As a result, there can occur a case that even after the workpiece is cleaned, placed onto the predetermined portion of the measuring machine, and then measured, the measurement result shows an abnormal value, requiring the workpiece to be again cleaned to remove from the workpiece an alien substance such as dust which is expected to be attached to the workpiece. This takes cost and time, and degrades the working efficiency as well as the reliability of measurement accuracy. Moreover, since the provision of the separate workpiece cleaning device incurs an increased cost. Besides, an operator has to always monitor the operation of the cleaning device, which forms a bar to realization of unmanned measurement.